Michelle Stanistreet, general secretary at the NUJ, said: “My members are not going to accept this cheap-as-chips pay offer when we know ITV is able to give Adam Crozier, its chief executive, a bonus of £8.4 million, and it has been on a £1.4 billion spending spree on organisation buy-ups while its staff face hardship because of their paltry pay.

”This dispute is easily sorted out. ITV needs to get back round the table to negotiate a sensible deal. NUJ members have consistently delivered great journalism and content that is the bedrock of ITV’s success.

“ITV’s success is down to a team effort. Staff have stuck by the organisation during the difficult times, but it is unfair and insulting that when profits are soaring and ITV is bullish about its financial future success, executives at the top are trousering huge amounts of cash while refusing to pay staff fairly.”

An ITV spokesperson said: “We were fully prepared to maintain an open dialogue with union representatives following the ballot result, which saw 226 union members voting to strike out of a UK workforce of 3,000 employees, but unfortunately industrial action is taking place today.

“We put contingency plans in place and our programmes this morning have been on air as usual, and will continue to be broadcast throughout the day and this evening, so viewers are unaffected by this dispute.

“We have made an above-inflation one year pay increase of 2%, effective from 1 January, which is on top of the 11.5% of pay rises over the last four years, some way ahead of other media sector pay awards.

“Eligible colleagues also received the maximum £1,200 bonus in their pay packets in March and we have increased the 2015 bonus opportunity to its maximum £1,500, which would be paid next year.

“ITV continues to make good progress but our focus on costs remains incredibly important across the business as we balance the need to continue to invest in growing the business, our people and the programmes that we create and broadcast.”